1. Field of the Invention
The present invention relates to an installation for curving or bending to convex form and tempering a sheet of glass.
The primary aim of the invention is to produce glass panels bordered by one or two lateral sections which are inclined to the flat portion of the panel at an angle ranging in value between a few degrees and 90.degree. .
2. Description of the Prior Art
There is known in particular, as disclosed in U.S. Pat. No. 4,784,681, an installation for uniformly curving a sheet of glass next to a furnace in which said sheet is heated to a sufficient temperature to ensure that the sheet is uniformly curved or bent to convex form. After heating, the sheet is brought into position between elements for shaping said sheet.
To this end, the installation is provided with means for applying the aforesaid elements on each side of the heated glass sheet so as to curve or bend this latter in accordance with the desired profile.
An essential characteristic of the installation described in U.S. Pat. No. 4,787,681 lies in the fact that the glass sheet is tempered by gas jets which are blown onto the sheet while it is engaged between the elements which bend the sheet. Moreover, these gas jets are blown by nozzles which are separate and distinct from the elements for shaping the glass sheet.
The chief disadvantage of this known installation lies in the fact that it does not permit the fabrication of glass panels having sections which make a large angle with the flat portion of the panels.
There is in fact a considerable demand for panels of this type.
Moreover, efficiency and uniformity of tempering are reduced by the fact that the tempering gas jets are blown in zones which are separate and distinct from those on which the elements for shaping the glass sheet are applied.
Patent No. WO-A-8901458 describes an apparatus for bending to convex form a glass sheet comprising an upper plate and a lower plate each composed of several elements joined to each other so that the two plates can assume the shape of a circular arc and the glass sheet located between the two plates can thus be given this arcuate shape.
In addition, these plates do not make it possible to form glass articles having a substantially flat central portion bordered on one side or on both sides by a section which makes a large angle with the central portion, for example between 30.degree. and 90.degree. .
The aim of the present invention is to overcome the disadvantages of the known embodiment aforesaid by creating an installation which makes it possible to increase the angle of curvature or of bending of the glass sheets and to improve the conditions of tempering of these latter.